Severe Vitamin D3 Deficiency in the Majority of Patients with Diabetic Foot Ulcers

Diabetic foot ulcers are a severe complication in patients with diabetes mellitus. Vitamin D is associated with impaired β-cell function and insulin resistance, and is necessary for wound healing and bone metabolism. We measured the serum concentrations of 25-hydroxyvitamin D₃ in 104 patients (63 inpatients, 41 outpatients) with diabetic foot ulcers and compared them to 99 healthy humans (control) and 103 patients with diabetes mellitus type 2 without diabetic foot ulcers. Calcium, creatinine, and parathyroid hormone were measured in patients with diabetic foot ulcers. The data were analysed together with glycosylated hemoglobin A1c and the severity of diabetic foot lesions according to the Armstrong classification. Levels of 25-hydroxyvitamin D₃ were lower (11.8±11.3 ng/ml, p<0.001) in patients with diabetic foot ulcers (mean age 70±12 years) than in the control group (27.2±12.2 ng/ml). No difference was found between in- and outpatients. Fifty-eight (55.8%) of patients with diabetic foot ulcers had a severe 25-hydroxyvitamin D₃ deficiency with levels below 10 ng/ml. Only 12% of the patients had 25-hydroxyvitamin D₃ levels above 20 ng/ml. Secondary hyperparathyroidism was found in 27.9% of patients and 11.5% of the patients were hypocalcemic. There was a negative correlation (r=-0.241) (p<00.1) between Armstrong classification and 25-hydroxyvitamin D₃ status. In conclusion, patients with diabetic foot syndrome are at high risk of 25-hydroxyvitamin D₃ deficiency. Thus, any patient with diabetic foot syndrome should undergo 25-hydroxyvitamin D₃ measurement and supplementation, if values are found to be decreased.